The invention relates generally to boundary layer growth through shockwave-boundary layer interaction, and more specifically to use of a micro-electromechanical system (MEMS) dielectric barrier discharge (DBD) based aerodynamic actuator to modify the boundary layer growth through a shockwave to mitigate flow losses.
When a shockwave reflects off a surface, the incident boundary layer sees an abrupt rise in pressure. This produces a correspondingly abrupt rise in boundary layer thickness, and often even causes the flow to separate. This is a significant factor in limiting the pressure that can be sustained across, for example, a turbomachinery stage. The ability to control and mitigate the losses associated with the shockwave-boundary layer interaction would advantageously enable higher stage pressure loading.
Boundary layer growth through a shockwave-boundary layer interaction is a well known fundamental problem that often limits the performance envelope of aeromechanical devices. Shockwave-boundary layer interaction on fan blades in certain engines, for example, contributes significantly to losses at high thrust levels.
Different techniques have been employed to modify the boundary layer interaction to control flow characteristics in the absence of a shockwave. Many of these well known techniques use passive methods and devices, while some others use piezo electric surface modifications for flow control. One known technique employs DBD devices to modify boundary layer interaction to control flow characteristics associated with an air induction system for an aircraft. Another known technique employs surface cavities to modify the boundary layer growth through a shockwave to mitigate flow losses.
In view of the foregoing, it would be advantageous to provide a self-contained aerodynamic actuator capable of modifying the boundary layer growth through a shockwave to mitigate flow losses, and that can be actuated at frequencies much higher than piezo electric surfaces, that is small enough to be incorporated into a thermal-barrier coating, that requires very little power to operate, that provides more versatility than passive techniques, and that can be incorporated into existing devices such as, without limitation, fan blades, turbine blades, compressor blades, and duct walls, with only minor modifications(s).